<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<HTML
><HEAD
><TITLE
>Control Functions</TITLE
><META
NAME="GENERATOR"
CONTENT="Modular DocBook HTML Stylesheet Version 1.79"><LINK
REV="MADE"
HREF="mailto:pgsql-docs@postgresql.org"><LINK
REL="HOME"
TITLE="PostgreSQL 9.1.2 Documentation"
HREF="index.html"><LINK
REL="UP"
TITLE="libpq - C Library"
HREF="libpq.html"><LINK
REL="PREVIOUS"
TITLE="Functions Associated with the COPY Command"
HREF="libpq-copy.html"><LINK
REL="NEXT"
TITLE="Miscellaneous Functions"
HREF="libpq-misc.html"><LINK
REL="STYLESHEET"
TYPE="text/css"
HREF="stylesheet.css"><META
HTTP-EQUIV="Content-Type"
CONTENT="text/html; charset=ISO-8859-1"><META
NAME="creation"
CONTENT="2011-12-01T22:07:59"></HEAD
><BODY
CLASS="SECT1"
><DIV
CLASS="NAVHEADER"
><TABLE
SUMMARY="Header navigation table"
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
><TR
><TH
COLSPAN="5"
ALIGN="center"
VALIGN="bottom"
><A
HREF="index.html"
>PostgreSQL 9.1.2 Documentation</A
></TH
></TR
><TR
><TD
WIDTH="10%"
ALIGN="left"
VALIGN="top"
><A
TITLE="Functions Associated with the COPY Command"
HREF="libpq-copy.html"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="10%"
ALIGN="left"
VALIGN="top"
><A
HREF="libpq.html"
ACCESSKEY="U"
>Up</A
></TD
><TD
WIDTH="60%"
ALIGN="center"
VALIGN="bottom"
>Chapter 31. <SPAN
CLASS="APPLICATION"
>libpq</SPAN
> - C Library</TD
><TD
WIDTH="20%"
ALIGN="right"
VALIGN="top"
><A
TITLE="Miscellaneous Functions"
HREF="libpq-misc.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
></TABLE
><HR
ALIGN="LEFT"
WIDTH="100%"></DIV
><DIV
CLASS="SECT1"
><H1
CLASS="SECT1"
><A
NAME="LIBPQ-CONTROL"
>31.9. Control Functions</A
></H1
><P
>   These functions control miscellaneous details of <SPAN
CLASS="APPLICATION"
>libpq</SPAN
>'s
   behavior.
  </P
><P
></P
><DIV
CLASS="VARIABLELIST"
><DL
><DT
><A
NAME="LIBPQ-PQCLIENTENCODING"
></A
><CODE
CLASS="FUNCTION"
>PQclientEncoding</CODE
>
     </DT
><DD
><P
>      Returns the client encoding.
</P><PRE
CLASS="SYNOPSIS"
>int PQclientEncoding(const PGconn *<TT
CLASS="REPLACEABLE"
><I
>conn</I
></TT
>);</PRE
><P>

      Note that it returns the encoding ID, not a symbolic string
      such as <TT
CLASS="LITERAL"
>EUC_JP</TT
>. To convert an encoding ID to an encoding name, you
      can use:

</P><PRE
CLASS="SYNOPSIS"
>char *pg_encoding_to_char(int <TT
CLASS="REPLACEABLE"
><I
>encoding_id</I
></TT
>);</PRE
><P>
     </P
></DD
><DT
><A
NAME="LIBPQ-PQSETCLIENTENCODING"
></A
><CODE
CLASS="FUNCTION"
>PQsetClientEncoding</CODE
>
     </DT
><DD
><P
>      Sets the client encoding.
</P><PRE
CLASS="SYNOPSIS"
>int PQsetClientEncoding(PGconn *<TT
CLASS="REPLACEABLE"
><I
>conn</I
></TT
>, const char *<TT
CLASS="REPLACEABLE"
><I
>encoding</I
></TT
>);</PRE
><P>

      <TT
CLASS="REPLACEABLE"
><I
>conn</I
></TT
> is a connection to the server,
      and <TT
CLASS="REPLACEABLE"
><I
>encoding</I
></TT
> is the encoding you want to
      use. If the function successfully sets the encoding, it returns 0,
      otherwise -1. The current encoding for this connection can be
      determined by using <CODE
CLASS="FUNCTION"
>PQclientEncoding</CODE
>.
     </P
></DD
><DT
><A
NAME="LIBPQ-PQSETERRORVERBOSITY"
></A
><CODE
CLASS="FUNCTION"
>PQsetErrorVerbosity</CODE
>
     </DT
><DD
><P
>      Determines the verbosity of messages returned by
      <CODE
CLASS="FUNCTION"
>PQerrorMessage</CODE
> and <CODE
CLASS="FUNCTION"
>PQresultErrorMessage</CODE
>.
</P><PRE
CLASS="SYNOPSIS"
>typedef enum
{
    PQERRORS_TERSE,
    PQERRORS_DEFAULT,
    PQERRORS_VERBOSE
} PGVerbosity;

PGVerbosity PQsetErrorVerbosity(PGconn *conn, PGVerbosity verbosity);</PRE
><P>

      <CODE
CLASS="FUNCTION"
>PQsetErrorVerbosity</CODE
> sets the verbosity mode, returning
      the connection's previous setting.  In <I
CLASS="FIRSTTERM"
>TERSE</I
> mode,
      returned messages include severity, primary text, and position only;
      this will normally fit on a single line.  The default mode produces
      messages that include the above plus any detail, hint, or context
      fields (these might span multiple lines).  The <I
CLASS="FIRSTTERM"
>VERBOSE</I
>
      mode includes all available fields.  Changing the verbosity does not
      affect the messages available from already-existing
      <TT
CLASS="STRUCTNAME"
>PGresult</TT
> objects, only subsequently-created ones.
     </P
></DD
><DT
><A
NAME="LIBPQ-PQTRACE"
></A
><CODE
CLASS="FUNCTION"
>PQtrace</CODE
>
     </DT
><DD
><P
>      Enables  tracing of the client/server communication to a debugging file stream.
</P><PRE
CLASS="SYNOPSIS"
>void PQtrace(PGconn *conn, FILE *stream);</PRE
><P>
     </P
><DIV
CLASS="NOTE"
><BLOCKQUOTE
CLASS="NOTE"
><P
><B
>Note: </B
>       On Windows, if the <SPAN
CLASS="APPLICATION"
>libpq</SPAN
> library and an application are
       compiled with different flags, this function call will crash the
       application because the internal representation of the <TT
CLASS="LITERAL"
>FILE</TT
>
       pointers differ.  Specifically, multithreaded/single-threaded,
       release/debug, and static/dynamic flags should be the same for the
       library and all applications using that library.
      </P
></BLOCKQUOTE
></DIV
></DD
><DT
><A
NAME="LIBPQ-PQUNTRACE"
></A
><CODE
CLASS="FUNCTION"
>PQuntrace</CODE
>
     </DT
><DD
><P
>      Disables tracing started by <CODE
CLASS="FUNCTION"
>PQtrace</CODE
>.
</P><PRE
CLASS="SYNOPSIS"
>void PQuntrace(PGconn *conn);</PRE
><P>
     </P
></DD
></DL
></DIV
></DIV
><DIV
CLASS="NAVFOOTER"
><HR
ALIGN="LEFT"
WIDTH="100%"><TABLE
SUMMARY="Footer navigation table"
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
><A
HREF="libpq-copy.html"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="index.html"
ACCESSKEY="H"
>Home</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
><A
HREF="libpq-misc.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
>Functions Associated with the <TT
CLASS="COMMAND"
>COPY</TT
> Command</TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="libpq.html"
ACCESSKEY="U"
>Up</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
>Miscellaneous Functions</TD
></TR
></TABLE
></DIV
></BODY
></HTML
>